Journal
MARINE CHEMISTRY
Volume 186, Issue -, Pages 178-188Publisher
ELSEVIER
DOI: 10.1016/j.marchem.2016.09.007
Keywords
Amazon River plume; Chromophoric dissolved organic matter (CDOM); Fluorescence; Excitation emission matrix (EEM); PARAFAC model; Principal component analysis; Photochemical degradation; Microbial degradation
Categories
Funding
- Gordon and Betty Moore Foundation (ROCA) [GBMF-MMI-2293, 2928]
- National Science Foundation (ANACONDAS) [OCE-0934095, OCE-1234388]
- National Science Foundation
- Directorate For Geosciences
- Division Of Ocean Sciences [1234388] Funding Source: National Science Foundation
Ask authors/readers for more resources
The Amazon River is a major source of terrestrially-derived dissolved organic matter (DOM) to the Atlantic Ocean. Measurements of dissolved organic carbon (DOC) and its optical properties (absorbance and fluorescence) were made in the water within and adjacent to the Amazon River plume during two cruises conducted at periods of low (September-October/2011) and high (July/2012) river discharges. Four fluorescent components were resolved by excitation emission matrix fluoresces combined with parallel factor analysis (EEM-PARAFAC) as two terrestrial humic-like components, one marine humic-like component, and one autochthonous protein-like component. The distribution and dynamics of optically active fraction of DOM were largely controlled by physical mixing along the Amazon River-ocean continuum, with the exception of the protein-like cornponent whose distribution was driven by factors other than dilution. Principal component analysis (PCA) enabled differentiation of water samples following gradient of terrestrial signatures and distinction of source materials associated with different fluorescent components. On board water incubation experiments with photochemical and microbial alterations revealed that photochemistry was primarily responsible for the removal of optically active fraction of DOM whereas the contribution of microbial transformation to this fraction was minor. Results from this work will provide a better understanding of DOM compositions and transformations in a globally significant river plume-ocean continuum. (C) 2016 Elsevier B.V. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available